The correct answer to this open question is the following.
Newspaper circulation changed from the 1900s to the 1930s in the following ways. The muckraker's journalists started to develop serious investigations about corruptive practices inside US politics, revealing a network of corruption in the government. Circulation increased because more people became interested in the news. It was President Theodore Roosevelt who coined the term muckraker in 1906. In that time, Yellow journalism led by William Hearst (New York Journal) and Joseph Pulitzer (New York World) managed the news in a sensationalistic way to attract more readers, and the circulation maintained its numbers.
